Constructional element



April 23,1929- 7 E.- J. DEWOITINE 1,710,350

CONSTRUCTIONAL ELEMENT Filed March '7, 1925 2 Sheets-Sheet i 2M -m DwmApril23, 1929. E. J. DEWO ITINE I CONSTRUCTIONAL ELEMENT Filed 'uarn v,1925 2 Sheets- Sheet Patented A r. as, 1929.

' nane EMILE JULIEN DEvVfillIll'E, OE QHATILLQH, FRANCE.

I COEiiTRUCTEONAL lELl F'llifEi l il T.

lippli'uzation. filed March 7,1925, Serial No. 1 5,749, and in BelgiumApril 18, 19:24.

relates to a simple and imsoars or lone'rons mients oit aeroa designatedthey are formed are utilized to greater ad vantage than has hithertobeen vthe'c'ase.

The constructional elements. or beams are oithe kind in whiehtheresisting moment is caused to vary in a continuous manner bysoproportioninp; height oi"? the beam' that at any sectionthe totalmoment of resistan'ceis as near as possible to the moment of fiexion dueto the load. I r l The esssential feature of the invention consistsintermingthe beams with plates -which are thinned away or diminished, in

. the direction of their'thiclrnessl The invention includes variousconstructional embodiments or arrangements which will be more fullydescribed hereafter, and as. new industrial products special partssuitable for their manufaetureas well as devices, especially aeroplanesprovided with beams or spars of theclass in'question;

In order that the invention may lJG'lllOl'G clearly understood, it willnow be described with r ference to the accompanying drawings, but it isto be observed that the de scription and drawings are way of example.

Figs. 1, 2, 3, .4- and 5,'inclnded in the drawings are allpartperspective views of beams or spars adapted to be fitted inposigivenmerely by tion and to worlr under flexion, and constructed according toas many method-sot carrying'out the invention.

In formi g work under flex-ion, and especially suitable for use as aspar in the Wing of an aeroplane, or a longron, the procedure 18substantially as follows.

It is known. that at each right section of a beam under transversestress, the material utilized must resist in particular a shearingstrain, a torsional strain'and especially a force of fiexion, thepredominant compo-.

nents of which correspond to the. flexion in the direction ofthe length,as for example 1n the case oi the longron orfspar'o'f. the

pendsfupon the section oi 1' ninimum. we rht; ally s;

ficient.

the beam or spar' intended. to

For this purpose the ment or beam may with advantage comprise,

wing of an aeroplanm the liexion due to thewidth oithe wing. v V

The resistance to the she; term he serial-devoted to the work. Thiscondition-is usu- L istied by the dimensions imposed by theother-forces, at any "ate to a certain t e i n the junction of the beam.

es upon tne polar momen ofinertia of .L L are section, which is alsogenerally sut- It is 1n the predominant directionwhich'must 'n ive theprincipal factors in the. structure jot inertia. lirom what has justbeen state 1, be seen that thebeam. must be constructed in such a waytiat whilst the material is judiciously' utilized both as regards priceY and weight, the res stingnioment of the whole shall vary in acontinuous manner from the port of attachment to the other extrei'nity',ant so that the strain on thewmaterial shall to the for e ottorsion dothe resistance to the force of fle'Xion it will I in all cases be asnear as possible to thead- LiSSllOlG limit, V i 7 It is also known thatwith equality of the modulus of section or the same rectangular frame,it is desirable to distribute the mass as. far as possible from theneutral line, but inorder to avoid buckling of a plate it is importantthat the'breadth shall have t the thickness ished by the addition of?one or a plurality of plates or extra thickness' an appropriate minimumratio; In nractlce the tendency tobuekle is dimin- In what follows asimple construction. is

described permittingg'platesor the like to be utilized the thickness ofWlllCll can be lessened at will and having a variable moment of inertia.

constructional eleand as shown atl igs. 1 and 2 which illustrateainethod of manufacture especially suitable for relatively smallspars'a: soliddrawn plate at having in the neighbourhood this case alsocomprise ribs Z) for the purposes already described. The structures maybe formed from plates 0 in e si l piece as indicated at Fig. 3 when'ltcllltl'crj for making such plates are available, but preferably thepractical COllSti'llQilOil is that indicated atlligs. l and 5 where eachconstructional. element comprises two parts (Z and a, one superposedabove the othu and attached to gether by means of rivets f. When.actually titted together longitudinal spaces are "formed boundedlaterally by a certain num- 301' of inner ribs These different l"' .dsot elem nts are uniform in width and are reduced in tra'isveri-iothickness by sawing; or pla ng as e case may be so that their sectionsdiminish regularly in the desired me iiier from the point of attachmentto the tree extremity oi the beam as shown at Figs. 1 and 3. Thisreduction in thickness is elleeteo on the opposite to that carrying the.reinforcing webs or ribs and also necessary at the extremities ot thesaid rib. Hence the Wing fiercurc members may have substantially thesame width throughout, but their transverse thicknes decreases, so thatthe portion of the member directl' adjacent the point of attachment tothe frame of the aeroplane has the greatest moment of inertia. As show uin the drawings, the WlCltllO'f a memher is greater than its thickness.As previously stated, the diminis iing thickness of the tlexure membermay besecured by shaping the main portion thereof, or the ribs, or both.

In some cases the element may comprise, whatever may be the arrangementadopted and shown atFigs. 2 and 5, between the ribs 5, a certain numberof extra ribs h In the foregoing manner 0.. constructional element isobtained adapted to be applied Whenever a beam or spar is requiredintended to work either under flexion as in the case for instance withthe spar of thewingr ot an aeroplane projecting outwards; or. underl'lexion and compression as in the case wing with several. suppm'ts andthe constructional element is found tulliii ments as already stated.

it is to be understood tl not limited to "c part eimir application orthe constructl embodimei which have been moi-s particularly described,but thet 1 modifications are included lia ling witl the claims.

*7 the inve. tion a interpretation w l fhatl claim and desire to secureby ters latent of the United Stwtes of linerica l. A structural elementfor aeroplane wi gs comprising a hollow rigid member de creasing intransverse tl-iicliness irom the point of attachment thereof to thefreeend thereof, the he" of .said' rigid .-.ow port r member ravine;rem'rorcmg web means of l rig-1d member hav a plurality of loi dinslexternal l'GiZ orcinp; ribs.

wing tleXure said element decreasing in thickness from one extremity tothe other, said member hav ing reent'orcing ribs ass elated therewithand extending externally thereof in the direction of its thickness. r 7'In testimony whereotl have hereunto set my hand.

EMILE JULIEN DltWOlllllll.

requiremember for aeroplanes do two body portions having conlongitudinalribs adapted to'hold"

